Brain Potentials (ERPS) Language, Memory, and Aging

描述(由申请人提供)：提出了一项为期五年的研究计划，旨在澄清在语言理解中使用的语义记忆和语义分析的组织确实在多大程度上确实相对避免了通常认为的正常老化过程。我们通过研究衰老对不同的子过程的影响来评估这一信念；更具体地说，通过(1)比较和对比涉及相同概念的不同感觉输入模式的加工--单词和图片；(2)检查语言中语义加工的两个不同因素--项目在其上下文中的语义整合以及随着上下文利用语义记忆在项目出现之前利用语义记忆来理解传入刺激的各种语义约束；(3)当一个大脑半球有轻微的加工开始时，比较整个大脑对单词和图片处理的反应；(4)考察个体在利用加工速度、抑制和工作记忆任务、强调感觉运动抑制的反眼跳任务、阅读广度任务和句子一致性阅读速度任务中的大脑/行为测量的个体差异。为此，我们分析了18-90岁的完好人类头皮记录的事件相关脑电位(ERPs)，以及他们在处理文字或图片时的伴随行为。24个实验操纵刺激(视觉的、图画的)和语境的情态(言语的、图画的)、刺激之间关系的性质(分类的、反义词的)、遇到特定项目的概率(完形概率)、是否以及如果是的话，项目在其上下文中的匹配程度、项目的约束程度和因此可预测的程度(词汇、语义)、输入的视野、任务或其组合。具体目的是确定正常衰老是否以及如果是的话，如何改变两个大脑半球对哪些词汇、语义和语境线索敏感，以及每个大脑半球如何使用它们来获取语义记忆和理解语言。在这样做的过程中，我们检验了(1)我们的假设，即虽然每个人都从背景中受益，但大多数老年人不同于年轻人，不使用它来预测即将到来的刺激的特征，尽管语言熟练程度的提高可能会弥补这一点；(2)Cabeza的假设，即老年人更有可能使用两个大脑半球来执行在他们年轻时只有一个人主要负责的认知功能；以及(3)众所周知的ERP效应与处理速度和认知功能的年龄相关变化之间的联系。这项研究项目将提炼出在语言处理和记忆使用过程中具有重要认知功能的ERP标记物。这一标准化数据库将对所有年龄段患有语义/语言处理障碍的成年人进行评估。

DESCRIPTION (provided by applicant): A five year research program is proposed which is aimed at clarifying the extent to which the organization of semantic memory and semantic analyses, as used in language comprehension, are indeed relatively spared from the normal aging process, as is commonly believed. We assess this belief by examining effects of aging on different subprocesses; more specifically, by (1) comparing and contrasting processing of different modes of sensory input that refer to the same concepts--words and pictures; (2) examining two distinct contributors to semantic processing in language-the semantic integration of an item within its context and the various semantic constraints that accrue as context taps semantic memory to make sense of incoming stimuli prior to an item's appearance; (3) comparing the whole brain's response to word & picture processing when one hemisphere has a slight processing headstart; (4) examining individual differences in brain/behavioral measures in tasks tapping processing speed, inhibition, & working memory, an anti-saccade task accenting sensorimotor inhibition, a reading span task, and a sentence congruity reading rate task. To these ends we analyze event-related brain potentials (ERPs) recorded from the scalp of (brain) intact humans between 18-90 yrs of age and concomitant behavior as they process words or pictures. Twenty four experiments manipulate stimulus (visual, pictorial) and context modality (verbal, pictorial), the nature of relations among stimuli (categorical, antonymic), the probability that a particular item will be encountered (cloze probability), whether or not and, if so, how well an item fits within its context, how constrained and thus predictable an item is and at what level (lexical, semantic), visual field of input, and task, or combinations thereof. The specific aims are to determine whether or not and if so, how, normal aging changes what lexical, semantic, and contextual cues the two hemispheres are sensitive to and how each uses them to access semantic memory and to make sense of language. In so doing, we test (1) our hypothesis that though everyone benefits from context, most older adults, unlike younger ones, do not use it to predict features of upcoming stimuli, though greater verbal proficiency may compensate for this, (2) Cabeza's hypothesis that older adults are more likely to use both cerebral hemispheres to perform cognitive functions that were in their younger years the primary responsibility of just one, and (3) links between well-known ERP effects and age-related changes in processing speed and cognitive functions. This research project will refine ERP markers of important cognitive functions in language processing and memory use throughout the lifespan. This normative database will be of value for the assessment of adults of all ages with semantic/language processing disorders.